I encounterd many of these in the North. The first one I killed on OP setings. The next time I saw two with a total of seven Carnos. I flew down on my Argy to see what they where attacking...and BOOM! Suddenly the Yuty took control of my argy! I couldn't control it! Next time I encounter one of these I will be more careful.
I have seen about three or more. One time there where two with a total of seven Carnos! I was flying on my Argy to see what they where attacking and then I flew too close. It took control of it and my argy looked like she was flying towards it. I thought I was done for but thankfully it only lasted about 20 seconds. I will never go that close again!
So there I was, flying along on my Argent, looking for Daeodons on the family server, and I spy a nearly max-level Yuty with his pack o' Carnos. Naturally - since I've never actually tamed a Yuty before - I messaged my dad to come help, since he was online. So I waited, and watched this pack of nasties chase a low-level Daeodon into the river. Didn't think much of it other than, "Stay out the way of that roar." They all kind of stopped in the frozen bits of the river, so I hopped off the bird and sniped out the Carnos from a safe distance. Dad arrived - "Is that Yuty stuck in the ice?" Turns out it was, and it glitched down into the water when we knocked it out. So we're both going, "Well crap, now it's going to drown." And then it didn't. Yuty tamed up, glitched back up through the ice, and I slapped him into a pod before any other weirdness had a chance to happen.